August 3, 2023
MY BAD VR TRIP
In an April article for The Verge, Sara M. Watson wrote of her first experience in VR. Despite having read accounts of VR sickness, Watson said she wasn’t prepared for how awful VR made her feel. Nausea hit before she even completed set-up, leaving her lying on the bathroom floor and unable to “unsee” the imprint of a virtual grid on the floor.
It may sound extreme, but such a reaction is not uncommon. There are reports of “VR hangovers” lasting hours following a five-minute simulation. Common physical symptoms include dizziness, headaches, and cold sweats, but VR users can also experience psychological effects like confusion and disorientation. Why is this?
UNDERSTANDING VR SICKNESS
Cybersickness occurs when your eyes see movement but your vestibular system - responsible for balance and spatial awareness - senses your body at rest. When screens aren’t involved, we call it motion sickness.
Watson points out that the visceral effects of VR are by design. Virtual reality is “embodied”—the whole point is for it to be as immersive as possible, which inevitably impacts or disrupts our senses including “our sense of safety and orientation.”
She talks of the mind-gut connection: Your brain in VR receives unexpected or conflicting signals. Your gut tells you that something’s not right by inducing nausea. “VR tolerance” comes down to how well you’re able to adjust to the conflict between what’s happening in the virtual world and what your body is doing in the physical world.
Advancements like higher frame rates and accurate motion tracking have helped to reduce motion sickness in VR. The vergence-accommodation conflict (VAC) which causes eyestrain and headaches, however, is more challenging to resolve. I’ll do my best to explain:
Vergence and accommodation form a reflex by which our eyes focus on a single object. Normally, they quickly and simultaneously adjust according to the same perceived distance of the object. In VR, you’re staring at a screen that’s just inches away from your eyes but trying to focus on a point in the simulated world that’s further away. Vergence and accommodation no longer match, making it hard to focus on close-up virtual objects.
BEST PRACTICES
There are already comfort ratings for most VR experiences, and VR headsets typically come with safety warnings for users with vertigo, anxiety disorders, epilepsy, inner-ear infections, etc. First-time VR users are advised to start slowly with simple apps and brief sessions in order to build up a kind of tolerance, and researchers are working on tools to help people better adapt to VR.
Jeremy Bailenson of the Virtual Human Interaction Lab at Stanford University says we should use VR only sparingly. He has proposed a framework for deciding if a scenario is worth exploring in VR: DICE. If an experience is Dangerous, Impossible, Counterproductive, or Expensive and rare to simulate in the real world, then it’s worth going virtual.
For their part, developers can lower the severity of motion sickness by moving virtual objects in and out of depth at a slower pace to give the user’s eyes more time to adjust and by not overlapping multiple virtual objects at widely varying depths. Introducing an artificial horizon in the virtual world can help, too, as can perfecting other depth cues like shading to reduce the cognitive load. These are just some VR user experience design best practices that can minimize the sensory conflict at the heart of VR sickness.
AFTERCARE
Even if - or, rather, when - we get the experience itself right – near-zero lag and lightning refresh rates – there is still the transition in and out of virtual reality to consider. VR can be incredible but also intense for some people, and frequent use “can take a toll on users,” explains Jeremy Bailenson--a physical toll, yes, but also psychological: The disorientation of being completely cut off from your surroundings, the isolation of the experience, etc.
Sara Watson advocates for “VR aftercare” or protocols for safely and comfortably emerging from the virtual world. She draws parallels to deep-sea diving and even BDSM in suggesting things like a decompression table (when a physiological threshold is reached, or the battery dies) and the selection of a safe word during setup to pause immersive experiences without taking off the headset.
CONCLUSION
Some people, me included, are just prone to motion sickness in cars. It doesn’t matter if it’s a rough-driving SUV or a smooth luxury sedan. In the same way, VR sickness will likely never be 100% preventable for all.
Image source: Vecteezy
